Apparatus for cracking petroleum oil



Match 29, 1938. c. P. DuBBs 2,112,360

APPARATUIS FOR CRACKING PETROLEUM OIL Original Filed July 5l, 1922 wiki"N v l Cear o?? P @H 65 rammed Mar'. 29, 193s 2,112,360

UNITED STATES PATENT. OFFICE carbon r. Dobbs, Newsiead, met, Bermuda,as- Y signor to Universal Oil Products Company,

Chicago, lll., a corporation of Delaware Original application July 31,1922, Serial No. 578,705. Divided and this application May 21, 1936,Serial No. 81,085

3 Claims. (Cl. 196-107) This application is a division of my co-pendingjected to the refluxlng action of the raw oil or application Serial No.578,705, filed July 31, v1922. returned condensate which is introducedto the This invention relates more particularly to dephlegmator throughthe manifolds 8, 9 and I0 apparatus for the conversion of higherboilingA petroleum oil into lower boiling point products. Among thesalient objects of the invention are to provide apparatus in which theoil vapors generated in an expansion or vaporizing chamber are relievedof their higher boiling point fraczone there is separated from the oilvapors the higher boiling point` fractions undesirable to the productionof a low boiling point distillate.

At the bottom of the dephlegmator leg in addition to the draw-off lineIB is a second draw- 10 tions in a dephlegmating zone so constructed tooffline 21 which is controlled by valve 28 through reduce the superheatof the vapors and-separate which a portion of the condensates separatedo ut out the higher boiling point products, and furin the dephlegmatortogether with quantities of ther controlling the temperatures ofdephlegmaraw oil which it may contain, may be drawn tion so that a moreuniform andbetter quality from the dephlegmator. This oil directed l5distillate passes over to the nnal condensing through the line 21 may bepassed through a cooler 29, thence through a line 30 regulated by a4valve 3l to a charging pump 32 from which it is pumped through the line33 to any one or all of the manifolds 8, 9 and I0 which are connected tothe line 33 by secondary connections 34, 35 and 36. The amount ofcondensate returned in this manner to the separate manifolds may beregulated by the, valves 31, 38 and 39 interposed in the secondaryconnections. Thus, it is obvius that in addition to the introduction ofraw oil to the manifold, the condensate may be also returned andintroduced` in regulated quantities with the raw oil so that an accuratel control may be had over the temperature conditions maintained in thedephlegmating column at all times.

The vapors which remain uncondensed in the dephlegmator pass overthrough the line 40 in which is interposed a valve 4|, to the watercondenser coil 42 mounted in the condenser box 43. The discharge end ofthe -condenser coil is connected by a line 44, regulated by a valve 45,to a distillate receiving tank 46.A The tank. is equipped with pressurerelief-valve 41, pressure stage.

In the drawing, the single figure is a diagrammatic side elevationalview of the apparatus.

Referring vin detail to the drawing, the oil to be treated is introducedthrough the line I which has separate connections 2, 3 land 4,controlled by valves 5, 6 and 1', respectively, to manifolds l, 9 andI0. The manifolds 9 and I0 are connected to circular roses or sprays I Iand I2, while the discharge end of the manifold 8 extends through the Tconnection I3 and into the vapor line I4 in the form of a perforatedpipe I5.

In introducing the oil to the system, it may be charged into themanifold Ill near the `top of the dephlegmator I 6 or into the manifold9 which is positioned intermediate of the top and bottom of thereiiuxing column, or it may be charged through the lower manifold andinto the vapor line through the perforated pipe I5 where it is chargednear the bottom of the dephlegmator directly into the vapor line. l

The oil combined with what condensate it may separate from the vapors in-the dephlegmating stage,'wil1 collect in the dephlegmatorjleg I1 fromwhich it is drawn oif through the line I8, controlled by the valve I9',and directed to the heating coils 25 mounted in the furnace 2|. Aconnecting pipe Y nishes a means for supplying additional raw oil to thecharging line, if desired. After passing through the continuous coil 2liin the furnace, the temperature of the oil has been raised to a crackingheat, and in this condition it is introduced in a fluid state to thevaporiaing chamber 24. In this enlarged chamber the oil is permitted tocollect, the vapors evolved .passing oi! through -the vapor line I4 andthe liquid unvaporized products being drawn of! through the-line 25which is regulated by the valve 25. The vapors passing through thedephlegmator Il are sub- 22, controlled by valve 23, fur` gauge 45.'liquid level gauge 49. A liquid drawoif line 50 connected tothe bottomof the tank is controlled by a valve 5I, and is connected to asexplained. In the dephlegmating or refiuxing the suction side of a pump52 by means of which the distillate may be charged back through the line53 to any of the manifolds 8, 9 or IIl through the separate connections54, 55 and 56, which are controlled by suitable valves. A line iii' isconnected to the draw-off line liqand is controlled by the valve 58whereby the distillate from 'the receiving tank may be withdrawn fromthe system instead of recycling it through the dephlegmating stage.

When thevapors from the expansion chamber are discharged into the bottomof the dephlcg mator without preliminary coo, the excess parts of therefluxing stag heat contained therein seriously interferes with thedephlegmating or proper reiluxing of the vapors so that the dephlegmatorcannot eiilciently separate or sift out the higher boiling pointfractions. Thus, owing to the superheat or excess heat of the vaporsfrom the reacting or vaporizing chamber, a greater part of thedephlegmator is used for extracting this excess heat before asubstantial amount of reiux condensation can take place. For thisreason, the superheat of the incoming vapors must .be reduced, and thisabsorption of heat by the reiuxing column exhausts to a great extent thecooling capacity of the dephlegmator, thereby reducing to that extentthe yeffectiveness of the apparatus in separating out the higher boilingpoint vapors. By cooling the vapors suflciently before orv just afterthey enter the dephlegmator a much more satisfactory separation of thehigher boiling point fractions may be obtained,

lit has been found that by controlling the capacity of the dephlegmatingstage through the introduction of cool oil in different parts of thedephlegmator a more satisfactory separation is obtained than when anapparatus, dependent upona radiating surface expo'sedto air, forcontrolling the capacity of the dephlegmating stage,

is used. e

It will be noted that by the pipe arrangement shown, it is' possible tocool or extract the superheat from the vapors in the vapor line prior totheir entering the dephlegmator or into the lower part of thedephlegmator. In doing t his the cool oil is introduced through theperforated pipe I5. this oil consisting of the raw oil or combined feedor raw oil, returned condensate, or a combination of the raw oil, reuxcondensate and pressure distillate from the receiving tank.

Further dephlegmation is obtained by introducing regulated combinationsof the oils mentioned to diiferent heights in the dephlegmator.

' It is understood, oi course, that oils differ in respect to theirtreatment, and the control oi' the dephlegmation will likewisenecessarily be altered with the different types 0f oil "treated Byproportioning the amount of cooling in the different l a moresatisfactory and complete control for sifting of the vapors can beobtained, and allows the capacity of a given size dephlegmator to besubstantially varied, for example-assume that the vapors in the vaporline have a temperature of from 800 to 820 F.,

these vapors may be cooled by the introduction l ofa cooling oil nearthe bottom of the dephlegmator to temperatures ranging from 600 to 700F., which will condense a large part of the vapors having high boilingpoint fractions, while the remaining vapors having high boiling pointcuts are condensed and thus separated out in the 1. An oil crackingapparatus comprising a heating coil and anenlargedchamber communicatingtherewith. a fractionator and means for passing vapors fromrthe chamberto the fractionator, a condenser -and receiver communicating with thefractionator, means for removing reilux condensate from thefractiona'tor, and means f for introducing charging oil, condensate fromsaid receiver, and portions of said reflux condensate into contact withsaid vapors prior to their introduction to the fractionator.

2. An oil cracking apparatus comprising a eating coil and an enlargedchamber communieating therewith. a fractionator and means for passingvapors from thev chamber to the fractionator, a condenser communicatingwith the fractiona'tor, means for contacting condensate formed in saidcondenser with said vapors prior to their introduction to thefractionator, and means for returning reflux condensate from theiractionator to said coil.

3. An oil cracking apparatus comprising a heating coil and an enlargedchamber communieating therewith, a fractionator and means forpassingvapors from the chamber to the fractionator, a condenser communicatingwith the fractionator, means for contacting condensate formed in saidcondenser with said vapors prior to their introduction to thefractionator, means for introducing additional condensate formed in,r

said condenser into the'fractionator, and means for returning reuxcondensate from the fractionator to said coil.

' CARBON P. DUBBS.

